42. Marc Jacobs

Marc Jacobs has "made fashion hip, but not inaccessibly hip," says Vogue editor Anna Wintour. Accessibly hip enough for him to build a $5 billion empire within LVMH that delights both the moneyed elite and the allowance-driven economy (his junk-store concept—$11 flip-flops, $55 rubber totes—is still thriving in the retail slump). Jacobs's knack for forecasting trends (this fall, neon and '80s nostalgia), anointing muses (hola, Anne Hathaway), and playing the media keep him in the spotlight. But it's his endless inspiration that drives sales. "It's very organic. We say, 'Let's make this happen and see what the reaction is,' " Jacobs says. "It's not like a creative person sits down with a mathematician. That's a hard thing for a lot of businesspeople to understand." — by Mark Borden